The present invention relates generally to brake control systems and more specifically to a digital computer brake control system.
The use of computers to control the braking system of a vehicle and more specifically a railroad vehicle is well known. They have generally been used to achieve a specific braking profile wherein the speed of the vehicle and the distance to stop are measured and then the required braking is calculated to bring the vehicle to zero velocity at the desired point. Typical examples are U.S. Pat. Nos. 3,519,805 and 4,005,838. Similarly computers have measured the velocity and acceleration and have used braking to maintain the vehicle at a required speed. An example of this is shown in U.S. Pat. No. 4,107,253. Computers have also been used to measure such variables as air brake pressure, wheel rotation, coupling forces between cars, locomotive velocity and wheel slip among others to provide traces of track profile, train presence upon the profile, car coupler force distribution and other train information to the operator. An example is illustrated in U.S. Pat. No. 4,042,810.
Although the computer controlled braking systems of the prior art just described are directed mainly to the more sophisticated application, they have failed to direct themselves to providing a more accurate braking control for normal braking. Similarly, the braking system of the light weight rail vehicles now used in the rapid transit system needs have not been met. The brake system for rapid transit rail vehicles have been individually designed for each rapid transit system. This is evolved since there is no need for uniformity as in the cross country rail system wherein cars must be interchangeable so that they may be connected to a multitude of different systems. Thus, each braking control system is designed with specific hardware to meet the needs of the individual customer. Thus, there is a need for a braking control system which is adapted to be tailored to individual system needs.
Mechanical brake control systems have been generally limited in the number of variables that they can use to affectuate appropriate braking. This has generally been limited to using an analog pressure in the brake pipe as the input signal and modifying it with a weight sensor to develop an appropriate braking pressure. Not only are the prior art mechanical braking control systems limited in the number of variables they use, but because of the environment, they require continual maintenance and replacement. Similarly the accuracy of the systems is somewhat limited.